DNA ANALYSIS USING AN ELECTROSPRAY SCANNING MOBILITY PARTICLE SIZER

A scanning mobility particle sizer (SMPS) allows size separation of ga s phase particles according to their electrophoretic mobilities. The a ddition of an electrospray source (ES) recently allowed extension of S MPS analysis to the macromolecular range. We demonstrate here the appl ication of ES-SMPS to nucleic acids analysis. Single- and double-stran ded DNA molecules ranging from 6.1 kDa (single-stranded DNA 20 nucleot ides in length) to 300 kDa (500 base-pair double-stranded DNA) were se parated and detected by ES-SMPS at the picomole to femtomole levels. T he measured electrophoretic mobility diameters were found to correlate with the analytes' molecular weights, while the peak areas could yiel d quantitative information. No fragmentation of DNA was observed under the conditions employed. Different apparent densities were observed f or single-stranded and double-stranded DNAs, showing a different behav ior for each type of biomolecule. The total analysis time was about 3 min/spectrum. Further optimization of ES-SMPS is expected to make it a fast and sensitive technique for biopolymer characterization.